One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,6)(5,8)(9,10,15,19)(11,16,21,23)(12,22,20,24)(13,17,14,18)(25,26)(27,35)(28,29)(30,34)(31,33)(32,38)(36,39)(37,40)(1,3,4,8)(2,5,6,7)(9,11)(10,16)(12,13)(14,20)(15,21)(17,22)(18,24)(19,23)(25,27,30,38)(26,32,34,35)(28,36,33,40)(29,37,31,39)(9,12,14,11,15,20,13,21)(10,16,17,22,19,23,18,24)(25,28,29,26,30,33,31,34)(27,36,39,35,38,40,37,32)(2,6)(5,7)(9,13,15,14)(10,17,19,18)(11,12,21,20)(16,22,23,24)(25,29,30,31)(26,33,34,28)(27,37,38,39)(32,40,35,36)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.